Immunohistochemical examination of anti-STn monoclonal antibodies LLU9B4, B72.3, and B35.2 for their potential use as tumor markers.

PURPOSE: Several investigators, including ourselves, have demonstrated by immunohistochemistry that in malignancy of colon, the tumor cells or cells adjacent to the tumor become reactive with anti-STn monoclonal antibodies, while in normal individuals the colonic cells do not react with anti-STn monoclonal antibodies. In the present study, an anti-STn monoclonal antibody LLU9B4 was generated in the laboratory by immunization of mice with STn extracted from LS174T, along with commercially available B72.3 and B35.5 anti-STn monoclonal antibodies for their sensitivity in staining colon cancer sections. RESULT: The results showed that 83.3% stained positive with 9B4 and 66.6% with B72.3, and there was no staining with B35.5 monoclonal antibody. The positive staining was mainly in the cells adjacent to colon cancer. It was also observed that the staining with LLU9B4 was much more pronounced than with B72.3.
CONCLUSION: Our study indicates that these antibodies may at least be more sensitive and specific for colon cancers than the current standard of care, FOBT.